Crankshaft journals machined incorrect
 

I have a forged 4340 crank with 4” stroke, 3” mains and supposedly 2.25” journals. I bought this 3 months ago and left in the box. I bought 428 Icon pistons at 1.595 compression height and 5140 I beam rods with 6.625 and 2.25. After bringing to machinist the journals are cut from the factory at 2.20. All literature and documents from the company say 2.25 journals. I believe when they changed over the cranks it accidentally was cut for the Chevy journals.

What is the best way to correct it? It’s a pain to return the crank and everything else on the crank checks out. But if I keep the crank I need new rods and maybe a custom piston? Do they make a thicker bearing shell so I can use my rods?

Your FIRST action should be to contact the folks you bought the crank from.

Yup, I did, no response yet, been a week. If they make good no problems. Looking for options.

I bought one that was supposed to be Pontiac Js and when I got it I checked and it was BBC

Is this one of the Speedmaster cranks?

Murf


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Another option. Sell your rods. Keep the pistons and the crank. Buy BBC 6.635 length rods. Only .010 taller, will put the pistons closer to zero deck height.
Make sure to get BBC rods which have a small end bushing because you'll need to re-bush them for the .010 smaller size Pontiac pin. You'll need to buy smaller bushings.

Yes, speedmaster for me, it’s too bad because the rest of the crankshaft checks out fine.

Only Ohio Crankshaft ever had a 3” main 4.00 stroke crank for Pontiacs but they discontinued it some time ago. I have to agree with the suggestion of selling your 6.625 inch rods and acquiring 6.635 BBC rods.

Can the BBC rods be sized down .010 from .990 to .980? Is there enough “meat” left in the bushing, or do I need new bushings? It about a 500hp build.

Youl'd need new bushings with a smaller ID.

Was your new pistons made for press or floating wrist pins?

Clay

Pistons are forged Icon for floating pins.

All your machine shop would have to do is order the correct bushings and hone them to the correct pin size.

Back in 2009 on a trip to the states I bought a 428 crank kit from star galaxy. It sat on the shelf till quite recently. I decided to assemble an engine a while ago and found I have the standard 428 pin height pistons with 6.7 rods and a 2.20 crank. As luck would have it I picked up a 428 block and crank for a good price . So now I need to buy a set of pistons to suit the 6.7 rods and crank and a set of 6.625 bushed rods. It would seem we need check our parts as soon as we get them. In my case due to the currant exchange rate it’s quite an expensive exercise

I picked up a forging over here in NZ recently, was stamped 4.250", but had 2.250 journals. Got the stroke checked, yep 4.250".
Waiting to do a mock assembly in the block. With an SRP flat top my last assemby ended up about 30thou in the hole and required a cut for zero deck.
Might get away with 4.25" and std 6.625 rod in this one (hopefully 🙄)

I will need to find those bbc bushings. Is the OD the common 1.017?

Jeggs have got advertised 3” main 2.25 “ journal 4.210 stroke cranks by speed master(cast) does anyone know if the 2.25 journal size is correct? I was about To order a couple but this thread has got me wondering as no other company will do the cast 455 crank with 3” mains and 2.25 journals. It would be good as I have a few parts to use up.

Mine was also a speedmaster. Based upon what is said so far in this thread seems hey are all BBC journals. Good lyck with speedmaster answer a email or phone call, no luck so far.
It’s ok for me with a bbc rods if I would have known ahead of time.

My 4340 Star Galexy Ohio 455 Crank from 2009 had BBC Rod Journals, and was out of Spec. They remachined it. So i got a "bargain". I had it trued-up in AL, and meets PMD Main Specs, and BBC rod Specs (-020).

Confident in it, but need a 6.625" AL rod, or...a a set of >\= 455+030 slugs for 6.8" rods.

Sorry to hear you are going through this issue. I bought one of their 4" stroke cranks during Black Friday sale too. After reading the thread reviewing the cranks I measured mine and found the same problem - glad I did. Speedmaster was easy to deal with on return - paid for shipping and full refund. See the thread here: http://forums.maxperformanceinc.com/...d.php?t=836084

You can buy the bushings here, they are about $10 ea., page 9 in the online catalog.

http://www.pppcenter.com

Not sure what size you'll need, for aftermarket rods it's hard to say. I just got done doing this for a current project.

https://live.staticflickr.com/65535/...1c0ecb70_c.jpg

Until you get one of the bushings removed from the rod, it can be very hard to measure for the new bushing OD. Due to the very thin wall, the only way I know of to get the bushing out of the rod is to bore it out on a milling machine, which is how I did it. The bushings are pressed in with a minimum .003" interference and this is very tight.

There is likely some more machining to do to get the new bushings to fit properly in the rod end. The rods will have to be heated and the new bushings pressed into the rod end when the sizes are correct. The .003" interference is very important to keep the bushing from spinning.


https://live.staticflickr.com/65535/...df257a07_c.jpg

Next you will need to drill the oil hole from the rod end through the bushing, and be sure the new bushing length is exactly the same width as the rod end (which it won't be) - more machining.

Then you can final hone the bushing ID to fit the pins.

Probably cheaper to buy new rods.